Cigarette smoking and risk of clinically overt thyroid disease: a population-based twin case-control study

BACKGROUND: The effects of cigarette smoking on the thyroid gland have been studied for years. However, the effect of smoking on thyroid function and size is still controversial. OBJECTIVE: To determine the impact of cigarette smoking on the development of clinically overt thyroid disease. METHODS: Matched case-control study of 132 same-sex twin pairs (264 individuals) discordant for clinically overt thyroid disease, ascertained from a population-based nationwide twin register. Information on thyroid disease and smoking habits was gathered by questionnaire, and the patients' endocrinologist or general practitioner verified the diagnosis. RESULTS: Overall, smoking was associated with an increased risk of developing clinically overt thyroid disease (odds ratio, 3.0; 95% confidence interval, 1.4-6.6; P = .003). This association remained statistically significant in monozygotic and dizygotic disease-discordant pairs. The effect of smoking was more pronounced in monozygotic vs dizygotic pairs (odds ratio, 5.0 vs 2.5; P= .04 for both). Essentially similar results were obtained after subdividing the twin pairs into groups discordant for clinically overt autoimmune (49 pairs) and nonautoimmune (83 pairs) thyroid disease. Among twin pairs concordant for smoking, probands with clinically overt autoimmune thyroid disease smoked significantly more than did their healthy co-twins (17 pairs; P= .03), whereas no difference was found between probands with nonautoimmune thyroid disease and their healthy co-twins (34 pairs; P= .20). CONCLUSIONS: Smoking is associated with an increased risk of developing clinically overt thyroid disease. Furthermore, our data suggest that cumulative cigarette consumption is a risk factor, most pronounced in autoimmune thyroid disease.     

Static magnetic fields affect capillary flow of red blood cells in striated skin muscle

Blood flowing in microvessels is one possible site of action of static magnetic fields (SMFs). We evaluated SMF effects on capillary flow of red blood cells (RBCs) in unanesthetized hamsters, using a skinfold chamber technique for intravital fluorescence microscopy. By this approach, capillary RBC velocities (v(RBC)), capillary diameters (D), arteriolar diameters (D(art)), and functional vessel densities (FVD) were measured in striated skin muscle at different magnetic flux densities. Exposure above a threshold level of about 500 mT resulted in a significant (P < 0.001) reduction of v(RBC) in capillaries as compared to the baseline value. At the maximum field strength of 587 mT, v(RBC) was reduced by more than 40%. Flow reduction was reversible when the field strength was decreased below the threshold level. In contrast, mean values determined at different exposure levels for the parameters D, D(art), and FVD did not vary by more than 5%. Blood flow through capillary networks is affected by strong SMFs directed perpendicular to the vessels. Since the influence of SMFs on blood flow in microvessels directed parallel to the field as well as on collateral blood supply could not be studied, our findings should be carefully interpreted with respect to the setting of safety guidelines.     

Low birth weight is not associated with clinically overt thyroid disease: a population based twin case-control study

OBJECTIVE: In recent years low birth weight has been proposed as a risk factor for the development of several chronic diseases in adult life, including diabetes and subclinical autoimmune thyroid disease. The association could, however, also be due to genetic or environmental factors affecting both birth weight and adverse health outcomes in adult life. Moreover, it is at present unknown whether or not low birth weight is associated with an increased risk of developing clinically overt thyroid disease. The aim of the present study was to investigate the impact of birth weight and several other birth characteristics on the development of clinically overt thyroid disease. DESIGN: A twin case-control study of same sex twin pairs. PATIENTS: One hundred and thirty-one same sex twin pairs (262 twin individuals) discordant for clinically overt thyroid disease, ascertained from a population based nation-wide twin register. MEASUREMENTS: Information about birth weight, birth length, birth order (first vs. second born), and prematurity was obtained from the original midwife records. RESULTS: Forty-nine twin pairs were discordant for clinically overt autoimmune thyroid disease (Graves' disease = 35 and Hashimoto's thyroiditis = 14) and 82 pairs were discordant for overt nonautoimmune thyroid disease (Simple goitre = 79 and toxic nodular goitre = 3). Overall, there was no difference in birth weights between probands and the healthy co-twins in monozygotic (MZ, n = 39) or in dizygotic (DZ, n = 92) pairs (MZ: mean +/- SE: 2619 +/- 93 g vs. 2553 +/- 89 g, P = 0.40; DZ: 2576 +/- 45 g vs. 2585 +/- 49, P = 0.86). By means of logistic regression, the impact of other birth characteristics such as birth length, birth order (first vs. second born), and prematurity was tested. None of the variables reached statistical significance. Subdividing the twin pairs into those discordant for clinically overt Graves' disease, Hashimoto's thyroiditis, and nonautoimmune thyroid disease did not change the results. CONCLUSIONS: This is the first study of the effect of birth weight and other birth characteristics on the subsequent development of clinically overt thyroid disease in which maternal, socioeconomic, and to a high degree, genetic factors have been controlled for. Our study did not show any effect of birth weight or any of the other birth characteristics on the risk of developing clinically overt autoimmune or nonautoimmune thyroid disease.     

Melde- und Informationssystem für bedeutsame Vorkommnisse bei Strahlenanwendungen in der Medizin: Struktur,Zuständigkeiten und Meldekriterien

The increasing frequency and complexity of medical radiation exposures to humans inevitably result in higher risks of harmful unintended or accidental radiation exposures. To ensure a high level of protection and its continuous improvement, the Directive 2013/59/Euratom thus requires to systematically record and analyze both events and near-miss events as well as, in the case of their significance, to disseminate information regarding lessons learned from these events promptly and nationwide to improve radiation protection in medicine. These requirements have been transposed into German legislation by the new radiation protection law and radiation protection ordinance that entered into force simultaneously on December 31^th, 2018. The reporting and information system as provided by these regulations as well as the tasks, duties and powers of the parties involved are presented in the first part of this review article. In the second part, the established application-specified criteria for the significance – and thus the notification requirement - of (near-miss) events are itemized and explicated.     

The effect of the application technic on the formal success of large-field radiotherapies

198 patients suffering from Hodgkin's disease or non-Hodgkin's lymphomas were irradiated with large-field techniques from 1979 to 1988. 129 of these were treated with common block techniques whereas the field-integrated dose modification (FIDM) was applied to 69 patients. Retrospective analysis shows that FIDM decreases acute toxicity. This was also evident in those patients who were irradiated by accelerated hyperfractionation. Although single doses were higher in patients treated with FIDM treatment had to be interrupted or abandoned less often than in those treated with conventional block techniques. Even high-risk patients could be irradiated more consequently.     

Pharmacokinetic Mapping of the Breast: A New Method for Dynamic MR Mammography

A dynamic contrast-enhanced MRI technique for whole breast examinations is presented. The fast kinetics of tissue response during and after constant-rate intravenous infusion of gadolinium diethylenetriaminopentaacetic acid was resolved using a strongly T₁-weighted saturation recovery TurboFLASH sequence that makes it possible to acquire signal-time courses sequentially from 15 adjacent slices with a temporal sampling rate of 21 s. On the basis of the mathematically established and experimentally verified linear relationship between the measured saturation recovery TurboFLASH signal variation and the gadolinium diethylenetriaminopentaacetic acid concentration in the tissue, the signal-time courses were analyzed within the framework of pharmacokinetic modeling. In our study, the tissue response was parameterized adequately using an open linear two-compartment model. With this approach, the tissue specific information contained in the signal-time course can be described using only two parameters: an amplitude A, reflecting the degree of MR signal enhancement, and an exchange parameter k₂₁, characterizing vascular permeability and perfusion of the tissue. A clearly arranged representation of the large amount of data (480 saturation recovery TurboFLASH breast images/examination) was accomplished by means of color coding of the computed parameters, resulting in one color-coded pharmacokinetic parameter map/cross-section.     

Extrathyroidal release of thyroid hormones from thyroglobulin by J774 mouse macrophages.

Thyroglobulin appears in the circulation of vertebrates at species-specific concentrations. We have observed that the clearance of thyroglobulin from the circulation occurs in the liver by macrophages. Here we show that the thyroid hormones T3 and T4 were released by incubation of mouse macrophages (J774) with thyroglobulin. Thyroid hormone release was a fast process, with an initial rate of approximately 20 pmol T4/mg per min and approximately 0.6 pmol T3/mg per min, indicating that macrophages preferentially release T4. The bulk of released thyroid hormones appeared after 5 min of incubation of macrophages with thyroglobulin, whereas degradation of the protein was detectable only after several hours. During internalization of thyroglobulin, endocytic vesicles and endosomes were reached at 5 min and lysosomes at 60 min. T4 release started extracellularly by secreted proteases and continued along the endocytic pathway of thyroglobulin, whereas T3 release occurred mainly intracellularly when thyroglobulin had reached the lysosomes. This shows that the release of both hormones occurred at distinct cellular sites. Our in vitro observations suggest that macrophages in situ represent an extrathyroidal source for thyroid hormones from circulating thyroglobulin.